Area Forecast Discussion
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565 FXUS62 KTAE 212112 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 412 PM EST Wed Jan 21 2015 .Near Term [Through Tonight]... A weak cold front extending from far southeast GA across the FL panhandle will sag through the area today and this evening. Northeast winds tonight will gradually increase to 5-7 mph overnight as mid and high level cloudiness increases from the west. Temperatures will be mild with lows in the mid 40s, as a low pressure system begins to take shape along the TX/MEX border. .Short Term [Thursday Through Friday Night]... In addition to the dry air spilling in behind the aforementioned front, zonal flow aloft and high pressure at the surface will limit rain chances on Thursday. The only exception will be once easterly flow becomes established over our Gulf waters, where enhanced convergence along an existing surface trough (seen clearly on vis imagery) should be enough to generate a few light showers. These showers will likely remain confined to the Gulf. Two distinct shortwaves currently present on WV imagery will play a significant role in our weather Thursday night through Friday night. The shortwave over the Central Great Basin will merge with another over the Southwest, resulting in an overall stronger system as it approaches the Southeast. At the surface, Gulf cyclogenesis will commence starting Thursday evening, with the low forecast to track across the northern Gulf, then through the Tri- State region Friday night. Ahead of the surface low, a deep warm front is expected to develop in the strong WAA regime ahead of the low pressure system. Strong upslope flow will be aided by a large area of diffluent flow aloft in the amplifying pattern. Further, an infusion of anomalously high tropical moisture will add to the aforementioned ingredients to warrant a heavy rain potential. Expect a large swath of warm frontal rain to spread across the region after midnight Thursday night, lingering into Friday afternoon. This will likely result in widespread average rainfall amounts of around 2 inches preceding the surface low and cold front. Another inch or so of rain will be possible area-wide with the passage of the cold front. As always, the the threat for severe weather around here will depend on just how much instability exists. While saturating rains on Thursday night into Friday will result in nearly moist adiabatic lapse rates, a strong focused low level jet could result in shear profiles favorable for tornadic development. Whether these storms could get surface based would be the main question, though it appears at least possible. Probably the best threat for any sort of severe weather would be late Friday afternoon into Saturday evening over the eastern Big Bend of Florida, where more favorable instability will align with strong deep layer shear. At this time the low-level jet wont be quite as strong and the threat would most likely shift to a damaging straight line wind potential. At this time, the potential for severe weather Thursday night through Friday night appears to be quite low, with high uncertainty. .Long Term [Saturday Through Wednesday]... In the wake of the aforementioned system, dry conditions will prevail through mid-week next week. Temperatures look to remain near seasonal levels both afternoon and night. && .Aviation... [Through 18Z Thursday] VFR conditions will prevail with light northeast surface winds and increasing mid to high clouds. && .Marine... Easterly flow will commence tonight, with winds and seas increasing to advisory levels Thursday night ahead of a strong frontal system. Gusts could reach gale force late Thursday night through Friday afternoon. Advisory conditions will continue through Saturday in the wake of the front, though gust should fall back below gale levels. Only a brief fall from headline levels will occur Saturday night into Sunday morning before another system threatens advisory conditions to end the weekend. && .Fire Weather... Moisture will increase as a low pressure system in the Gulf moves through. A wetting rain is expected Thursday night into Friday. Dispersions are low as transport winds will be light on Thursday. No fire weather concerns at this time. && .Hydrology... All area rivers remain below flood stage with steady or decreasing water levels. The forecast 2-3 inch rainfall amounts Thursday night through Friday night would result in rising river levels, though only rivers impacted by the isolated higher rainfall amounts would risk reaching flood stage. && .Preliminary Point Temps/PoPs... Tallahassee 47 68 58 65 49 / 0 10 70 90 50 Panama City 50 64 58 64 49 / 0 20 80 90 40 Dothan 44 60 51 55 43 / 0 10 80 90 40 Albany 41 61 49 55 46 / 0 0 80 90 50 Valdosta 46 66 56 63 51 / 0 0 60 90 70 Cross City 50 73 58 68 56 / 0 0 30 80 80 Apalachicola 50 65 58 66 52 / 0 20 70 90 40 && .TAE Watches/Warnings/Advisories... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...HOLLINGSWORTH SHORT TERM...HARRIGAN LONG TERM...HARRIGAN AVIATION...HOLLINGSWORTH MARINE...HARRIGAN FIRE WEATHER...WESTON HYDROLOGY...HARRIGAN is the U.S. government's official web portal to all federal, state and local government web resources and services.